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HomeMy WebLinkAboutSewer System Reportwx Sewer System Report for University Heights Phases 1 -5 College Station, Texas May, 2011 Prepared By: SCHULTZ ENGINEERING, LLC. TBPE Firm Registration No. 12327 2730 Longmire, Suite A College Station, Texas 77845 979.764.3900 r• 1, S * c it i•i•• "N JOSEPH P. SCHULTZ s 65889 4 A ree1 0. " Z3 _1 1 F-12327 SCHULTZ ENGINEERING. LLC. I ' J) General Information Location: General Note: Offsite Flow Assumption: It was assumed that the land to the west would have 40 dwelling units that could use the provided stubbed out sanitary sewer line. The flow from the 20.305 acre Kemp tract to the north was determined by assuming 4 DU per acre per its residential land use. Land Use: Design Criteria Primary Sewer Outfall: The University Heights Subdivision, Phases 1 -5, Lots 1 -153, Blocks 1 -10, is located on the west side of Holleman Drive South and north of Paloma Ridge Drive. These 153 residential lots will flow into the proposed 10 ", 8" and 6" sewer lines which are to be constructed with these Phases. These sewer lines will connect to an existing manhole on the existing 12 "sewer line that drains to the Steeplechase Sanitary Sewer impact fee sanitary sewer line. This is located to the south and was constructed in with previous development. Single Family Residential — Phases 1, 2 and 3 Multi- Family Residential — Phases 4 and 5 20 DU per acre Phase 4 — 3.454 x 20 = 69 DU, Phase 5 — 5.141 x 20 = 103 DU An existing 12" sewer line through Las Palomas subdivision. Domestic Demand: Avg. Pop Density: 2.67 persons per unit Average Flow: 100 gpd /cap Residential Peaking Factor: 4 10% Infiltration Assumed Pipe: PVC ASTM D 3034 SDR 26 Applicable Exhibits: Exhibit A — Sanitary Sewer System Layout Exhibit B — Sanitary Sewer Analysis Spreadsheet Conclusion The proposed 10 ", 8" and 6" lines flow into an existing manhole previously constructed with separate development. The analysis in Exhibit B checks the calculated slope required to pass the estimated flow against the design slope shown on the plans. The spreadsheet indicates the design slope is greater than the minimum computed slope, so we conclude that the system is more than capable of carrying the anticipated flows from this phase and future phases of the subdivision. Exhibit B also shows the full flow velocity in the proposed lines to range from 2.81 fps to 1.98 fps and the calculated peak flow velocity to range from 0.29 fps to 1.45 fps.